One of the great ironies of the fact-checking enterprise is that despite their mission to bring transparency and truth to the marketplace of ideas, fact checkers themselves operate largely as black boxes. Arguing they are businesses rather than public services, fact-checking sites refuse to answer even the most basic questions about their inner workings. As Facebook’s financial influence over the fact-checking landscape grows, new questions arise about fact checkers’ financial transparency and external influences.

Last month The Guardian published a critical look at the relationship between fact-checking sites and Facebook. Among the issues raised were concerns that Facebook’s financial support of the sites was creating implicit pressure for them to adhere to Facebook’s idea of what should or should not be fact checked.

Facebook has quickly become an important funder of fact-checking operations. Snopes received $100,000 from the social media giant in 2017. PolitiFact has refused to release specific numbers, but has stated that the revenue is substantial enough that it “added to our overall sustainability.”

At the same time, Facebook provides its partners with an internal portal that lists the stories the company wants to see fact checked. While Facebook notes that its partners are “under no obligation to fact-check anything from the list,” this creates a situation in which fact checkers may feel an implicit obligation to prioritize content from the list in order to maintain their funding.

In fact, Snopes founder David Mikkelson noted to TechCrunch that the $100,000 it received was at least in part because Facebook had placed bounties on specific high-profile political stories. He clarified that many of the stories were already on its radar and that Snopes was not obligated to focus on claims identified by Facebook. Yet, just knowing that Facebook places a financial premium on political stories is enough to raise concerns regarding whether fact checkers’ obsession with President Trump is at least partially motivated by their benefactor.

Mikkelson did not respond to a request for more details on the kinds of political stories that Facebook had prioritized or other details of the funding arrangement.

For its part, PolitiFact issued a statement also denying that Facebook plays any role in which stories it fact checks. However, when asked to clarify its arrangement with Facebook, PolitiFact Executive Director Aaron Sharockman described the relationship in terms of a commercial contract, rather than a gift: “Facebook pays us a fee for a service. … They pay us for sending them fact checks of misleading or incorrect information.” With respect to how PolitiFact selected which stories to review, he offered that “we are in full control of what material we provide [Facebook] and are not bound by any list provided to us by Facebook. Facebook pays us the same amount no matter what material we choose to provide them (from their list or not), and they have no say in what that the material is, or the conclusion of our work.”

However, when asked whether PolitiFact had ever received feedback from Facebook regarding how well it was meeting the company’s needs in terms of topical or story focus, he declined to comment. He also stopped short of explicitly denying Snopes’ claims that Facebook placed financial premiums on certain stories.

At the same time, we cannot independently verify any of these denials. PolitiFact has steadfastly refused to provide a copy of its contract with Facebook that would outline its obligations and pay structure.

Even if fact checkers are not contractually required to focus on what Facebook wants them to, having a major funder provide them a list of the stories it wants assessed creates at least the appearance that continued funding might be threatened if they never select anything from the list. Further, if Facebook offers partners a financial bonus for selecting specific stories or topics, it reinforces that those are the topics it views as most contingent upon its continued financial support.

As Facebook ramps up to provide its partners with “quarterly reports” on the “impact of their efforts” there will be an even greater implied connection between continued funding and how well they prioritized Facebook’s demands.

Of course, fact-checking costs money and it is not realistic to expect that Facebook should benefit from the work of fact checkers without supporting them. However, instead of writing checks directly to fact checkers, it could partner with outside foundations, providing those foundations a multi-year fixed block grant to disburse without its involvement.

Strangely, while the International Fact-Checking Network’s Code of Principles requires “transparency of funding,” PolitiFact does not actually list Facebook as a funder as of July 2018. When asked why, Sharockman clarified that “we choose not to detail exact payments on our website, because unlike a grant or donation, we are charging Facebook for a specific product delivered (a fact check). We have more than a dozen relationships like this, most notably with television stations and newspaper publishers across the country who pay for access to our work in a way similar to Facebook. We also do not detail revenue generated by advertisements on our website.”

When asked whether these other funders similarly provide PolitiFact with priority lists of stories they wished to have fact-checked or whether they were merely paying a syndication fee to republish PolitiFact’s content as is, he declined to comment.

Asked about PolitiFact’s compliance with the IFCN Code of Principles, IFCN Director Alexios Mantzarlis offered that since PolitiFact is part of IFCN’s parent organization, the Poynter Institute, rather than a stand-alone operation, it was not required to list all of its funders. When asked whether organizations can be penalized for not listing all of their funders, he noted that PolitiFact “is at worst partially compliant” with this requirement. He conceded, however, that he had “encouraged them to list all major contracts and will be discussing this with the Board too.”

Why does all of this matter? It matters because we have near-zero visibility regarding the inner workings of the organizations that today have the power to decide what we’re allowed to talk about online.

Organizations that freely attack others for not carefully choosing their words see nothing wrong with touting financial transparency while shielding their own benefactors under the argument that a “donations” page need not list “contractual” funding. Without a fuller understanding of who underwrites the fact-checking landscape and what rights those organizations assert in their contracts, we cannot be assured of fact checkers’ neutrality. The growing influence of Facebook is of particular concern, especially given the risk that it could push fact checkers to focus more heavily on certain topics or stories out of an implicit fear they might otherwise lose that critical funding.

After all, Trump has been a clear favorite target of fact checkers, but has that been due, at least in part, to Facebook’s influence?

In the end, the fact that we cannot answer any of these questions should serve as a wake-up call: We know far too little about the outside influences on these ultimate arbitrators of the facts and how those forces may be silently shaping what is “truth” in the web era.

RealClear Media Fellow Kalev Leetaru is a senior fellow at the George Washington University Center for Cyber & Homeland Security. His past roles include fellow in residence at Georgetown University’s Edmund A. Walsh School of Foreign Service and member of the World Economic Forum’s Global Agenda Council on the Future of Government.